BEIRUT - The head of the militant Shiite Hezbollah movement on Sunday defended the decision to bring down Lebanon's government, arguing that the move was necessary to protect the country from the consequences of indictments expected soon from a controversial United Nations tribunal.

The comments from Hassan Nasrallah - his first public remarks since the government's collapse - set the stage for what are likely to be lengthy negotiations on forming a new government, stalling Lebanese institutions and frustrating the nation.

Hezbollah and its allies resigned from the government Wednesday to protest Prime Minister Saad al-Hariri's refusal to renounce the work of a U.N. tribunal investigating the 2005 killing of Hariri's father, former prime minister Rafiq al-Hariri. The move follows a long standoff over the tribunal that has paralyzed the country, pitting Hariri, backed by the United States and Saudi Arabia, against Hezbollah, which is backed by Syria and Iran.

Parliamentarians are expected to meet Monday to nominate a new prime minister for this tiny coastal nation of Sunni and Shiite Muslims and Christians that has long been a regional battleground for influence.

Political leaders here are deeply divided, and choosing a new government will prove difficult if a compromise is not reached. Nasrallah vowed that members of the March 8 alliance, led by Hezbollah, would not back Hariri, who is now serving as a caretaker prime minister. Instead, the group and its allies are trying to gather the parliamentary support they need to select someone for the position.

"It was our moral and patriotic duty to make this government fall in order to open a door to form a strong government," Nasrallah said in his address on the Hezbollah television channel Al Manar. "This step was constitutional, legal and civilized. We did not go to the streets or use weapons."

Sealed draft indictments in the 2005 assassination will be sent soon to the pre-trial judge at the tribunal, and they are widely expected to implicate several of Hezbollah's members. The group has staunchly denied involvement in the killing of Rafiq al-Hariri and 22 others and has demanded that the government stop cooperating with the tribunal.

"They could not make a plan to deal with the indictments," Nasrallah said, adding that the Hariri-led administration "exposed" the country and had become "incompetent." He added, "We exercised our beliefs for the sake of our country."

Both the pending indictments and the related political crisis are sensitive issues in a nation that on the surface seems calm but is, in fact, deeply divided by religion and sect and often teeters somewhere between peace and conflict.

On the radio in Beirut, one weekend news bulletin summed up things in just four words: "The toughest week ahead."

Nasrallah asked why the "world is interfering" in an internal issue, referring to Western and Arab countries that have rallied behind Hariri. Before signing off, he warned Hariri that the deposed dictator in Tunisia, Zine El Abidine Ben Ali, was an ally to the West, but those friends quickly turned on him and no Western airport opened its doors after his people ousted him from power.

"There is a huge responsibility tomorrow on the members of parliament to decide the destiny of the country," he said.

Such uncertainty is the norm in Lebanon, whose institutions have been stalled intermittently since the 2005 killing.

Most people here agree that an internal war will not engulf Lebanon. Many say they don't want to fight, and only one party is strong enough to win, the armed Shiite movement of Hezbollah, founded nearly 30 years ago when Israel invaded Lebanon. In 2008, Hezbollah showed its military might when it took to the streets and briefly took control of parts of the city.

"They could have kept the city, they could have taken it all, but they didn't. They just wanted to show that all of this is a play," said Ahmed Waheed, 45, as he hawked meat pies on the side of the road in the northern city of Tripoli. "We want the truth but these politicians have taken us into a dark tunnel, and we don't know where we are anymore."

Around him, banners graced the bridges and traffic circles of this city. "Whoever betrays Saad Hariri, betrays Lebanon," reads one in the center of the mostly Sunni city where Hariri has wide support.

"They fight with each other so they can get paid from the outside," Waheed said. Most months, the Sunni man can't make his rent. He steals his electricity because he can't pay for it, and every time there is a crisis, food prices rise. His wife holds a master's degree but she can't get a job. "We want to protest, but there is no government to protest."

Waheed's frustrations are echoed across the country.

In south Beirut, the Shiite heartland of the Lebanese capital, Hassan Ramadan squeezed fresh juice for his customers on Sunday. The front of his store was adorned with a picture of Nasrallah.

He and his family had a store in Tarik al Jadida, a Sunni district of Beirut where sectarian skirmishes were most fierce in 2008. Sunni men from the neighborhood destroyed his store because it was Shiite-owned. He still hasn't reopened. The time to do that is not now, he said, because the sectarian tensions are too high.

"Lebanon is always in a crisis," Ramadan said. "When the leaders sit together and agree, the people will calm down and everything will be okay. The politicians decide the safety of the streets."

"Lebanon is a battlefield for the whole world," added his customer Mohammed Srour as he dipped his plastic spoon into a cup of sliced fruit and fresh juice.

fadell@washpost.com Special correspondent Moe Ali Nayel contributed to this report.